A construction machine such as hydraulic shovel includes a lower travel portion 80, an upper revolving portion 81, and a work equipment 82 which is connected to this upper revolving portion 81, as shown in FIG. 11. In addition, the work equipment 82 includes a boom 83 which protrudes from the upper revolving portion 81, an arm 84 which is connected to this boom 83, a bucket 85 which is mounted to this arm 84, and so on. Additionally, the boom 83 swings by operation of a boom cylinder mechanism 86. The arm 84 swings by operation of an arm cylinder mechanism 87. The bucket 85 swings by operation of a bucket cylinder mechanism 88.
Furthermore, the aforementioned cylinder mechanism 86, 87 and 88 are hydraulically operated. Accordingly, a hydraulic circuit with a hydraulic fluid tank is constructed. A hydraulic fluid tank with a divider plate which divides the interior thereof is known (for example, see Japanese Patent Laid-Open Publication TOKUKAI No. HEI 5-321902). In a hydraulic fluid tank stated in the foregoing Patent Document 1, a box-shaped tank main member 90 is provided with a divider plate 92 parallel to a bottom plate 91 of this tank main member 90, as shown in FIGS. 9 and 10. In addition, a drawing port 93 is opened in the bottom plate 91, and a return port 94 is located above the divider plate 92. That is, the tank main member 90 stores hydraulic fluid, and a hydraulic pump draws the hydraulic fluid of the tank main member 90 through the drawing port 93. Return hydraulic fluid from the cylinder mechanisms (actuator) 86, 87 and 88 is returned to the tank main member 90 through the return port 94. Additionally, in this hydraulic fluid tank, the divider plate 92 is provided with a hole 95 for a filter (strainer) 97 and a number of holes 96.
That is, in this hydraulic fluid tank, in a case where the fluid surface sways, the divider plate 93 disturbs the upward movement of the fluid surface to prevent that the filter 97 located under the divider plate 92 is exposed to air.